High-impact-resistance low-temperature denitration catalyst and preparation method thereof

Abstract

The invention provides a high-impact-resistance low-temperature denitration catalyst and a preparation method thereof, and belongs to the technical field of denitration catalysts. The low-temperature denitration catalyst is mainly prepared from a metal carrier, manganese dichloride, metatitanic acid, ferric chloride hexahydrate, deionized water, a hydrochloric acid solution, titanium dioxide, silicon-based resin, triglycidyl isocyanurate and the like. The prepared denitration catalyst layer not only has excellent adhesive force with a metal carrier, but also has good impact resistance, the catalyst layer is free of cracking and falling phenomena after being impacted by 50cm, the denitration catalyst layer is superior to a common denitration catalyst layer formed by adopting an impregnation method or a precipitation method, the metal catalyst active matter is prepared by compounding manganese, titanium and iron elements, and the preparation method is simple and convenient. The low-temperature denitration effect is good, the NOx conversion rate at the temperature of 180 DEG C can reach 86% or above, water resistance is good, no obvious change occurs after boiling in boiling water for 20 min, and the denitration catalyst has the advantages of saving denitration energy consumption, being long in service life, not prone to loss and the like.

Description

Technical Field

[0001] The invention belongs to the technical field of denitration catalysts, and in particular relates to a high-impact-resistant low-temperature denitration catalyst and a preparation method thereof. Background Art

[0002] At present, in the exhaust gas denitrification reaction, the substance that prompts the reducing agent to selectively react with the nitrogen oxides in the flue gas at a certain temperature is the most commonly used catalyst V 2 O 5 / TiO 2 series, and the commonly used carriers are basically formed by oxide carriers such as aluminum oxide, titanium oxide, etc., and the active components of the catalyst such as vanadium elements are adsorbed on the carrier by impregnation or precipitation to carry out catalytic reaction. Since the denitrification catalyst is easily subject to collision, air flow vibration, etc. during transportation and use, on the one hand, the carrier is easy to break and the catalyst layer has insufficient impact resistance. In addition, due to the impregnation and precipitation methods, the adsorption capacity of the active components of the catalyst on the carrier is poor, the adhesion is insufficient, and it is easy to fall off and lose during use, resulting in poor activity and stability of the catalyst layer. Moreover, although vanadium-based catalysts have been commercially used as active components, they also have some shortcomings. For example, their catalytic activity is high at high temperatures (320-400°C), NO x The conversion rate can reach more than 90%, but the catalytic activity is low at low temperatures such as 200°C and below, and it is not suitable for low-temperature denitrification reactions. The current industrial gas boiler flue gas emission temperature is generally 150-190°C, because the vanadium-titanium catalyst has a low NO conversion rate in this temperature range. x The conversion rate is low, generally below 70%. How to develop a new denitration catalyst to achieve denitration catalysis in this low temperature range and improve the catalytic activity of the catalyst at low temperatures, so as to solve the problem of direct denitration treatment of gas boiler flue gas. In this way, there is no need to reheat the exhaust gas of the gas boiler to above 320°C for denitration treatment, which not only saves energy but also simplifies the treatment process. Summary of the invention

[0003] In view of the above problems, the present invention provides a high-impact-resistant low-temperature deNOx catalyst and a preparation method thereof. A specific manganese-based catalyst is combined with titanium and iron elements to form a hybrid catalyst active component, which is prepared into catalyst powder with a specific silicon-based resin and triglycidyl isocyanurate. The catalyst powder is then electrostatically sprayed and high-temperature cured on a metal carrier to form a low-temperature deNOx catalyst with high adhesion and high impact resistance.

[0004] One of the purposes of the present invention is to provide a low-temperature denitration catalyst with high impact resistance.

[0005] The second object of the present invention is to provide a method for preparing the high impact resistance low-temperature denitration catalyst.

[0006] In order to achieve the above-mentioned purpose of the present invention, the following technical solutions are particularly adopted:

[0007] In a first aspect, the present invention provides a high impact resistance low temperature denitration catalyst, the high impact resistance low temperature denitration catalyst comprising a metal carrier and a catalyst layer on the metal carrier;

[0008] The catalyst layer comprises the following components by mass: 100-120 parts of active components, 15-18 parts of silicone-based resin, and 0.8-1.0 parts of triglycidyl isocyanurate;

[0009] The active component is prepared from the following raw materials in molar proportions: 6-8 parts of manganese dichloride, 1.5-2 parts of metatitanic acid, 5-7 parts of ferric chloride hexahydrate, 30-35 parts of deionized water, and 6-8 parts of titanium dioxide;

[0010] The silicon-based resin is prepared from raw materials including the following molar proportions: 15-23 parts of xylene, 6-9 parts of 1,6-hexanediol, 4-7 parts of dimethyldimethoxysilane, 7-10 parts of methylphenyldimethoxysilane, 3-5 parts of trimethylolpropane, and 4-5 parts of succinic anhydride.

[0011] In some embodiments, the metal carrier is a multi-layer tinplate, with 4-6 layers and a layer height of 3-5 cm, wherein the tinplate is provided with circular holes, and the interval between each two holes is 2-3 cm. The tinplate can be circular, square, etc.

[0012] In some embodiments, the active ingredient is prepared by a method comprising the following steps:

[0013] Add deionized water, manganese dichloride, metatitanic acid, and ferric chloride hexahydrate into the reaction kettle according to the formula, stir and heat to 80-85°C, and after the solution is basically dissolved, add 30-32% hydrochloric acid by mass to adjust the pH value of the system to 4-5, continue to stir and react for 1-1.5h, and after the pH value is detected to be stable, add the formula amount of titanium dioxide and stir and mix thoroughly for 0.5-1h to form a uniform slurry, then discharge the material;

[0014] Then put it into a blast oven and dry it until the volatile matter is less than 3%, the oven temperature is 110-120°C; then transfer it to a muffle furnace for high-temperature calcination for 4-5 hours, the calcination temperature is 380-420°C; after calcination, cool it to room temperature, and crush and sieve (140-160 mesh) to obtain the active component.

[0015] In some embodiments, the raw materials for preparing the silicon-based resin further include: a catalyst, wherein the catalyst is dibutyltin dilaurate, and the amount used is 0.8-1.2% of the mass of 1,6-hexanediol.

[0016] In some embodiments, the silicon-based resin is prepared by a method comprising the following steps:

[0017] A. Add the formulated amount of xylene, 1,6-hexanediol and catalyst into the reactor, raise the temperature to 120-125°C, then add the formulated amount of dimethyldimethoxysilane and continue the polymerization reaction at 120-125°C;

[0018] B. Take samples and test them by gas chromatography. When the content of free dimethyldimethoxysilane is less than 5%, add the formulated amount of methylphenyldimethoxysilane and raise the temperature to 130-135° C. to continue the chain extension polymerization reaction;

[0019] C. Take samples and test them by gas chromatography. When the content of free methylphenyldimethoxysilane is less than 1%, it indicates that the basic reaction of the organosilicon monomer is completed. At this time, add the formulated amount of trimethylolpropane and heat it to 150-155°C to carry out high-branching chain extension polymerization reaction. During the heating process, the xylene solvent in the system is removed;

[0020] D. Take samples to test the hydroxyl value of the polymer. When the hydroxyl value of the polymer reaches 48-55 mgKOH / g, add the formulated amount of succinic anhydride and raise the temperature to 160-163°C to carry out carboxyl-terminated polymerization. When the acid value of the polymer reaches 25-30 mgKOH / g, discharge the material at high temperature, cool it on a steel belt, and crush it to obtain a silicone-based resin product.

[0021] In some embodiments, triglycidyl isocyanurate has an epoxy equivalent of 102-107 g / mol and can be purchased from Changzhou Niutang Chemical Plant Co., Ltd.

[0022] In a second aspect, the present invention provides a method for preparing the above-mentioned high impact resistance low-temperature denitration catalyst, comprising the following steps:

[0023] The active component, silicone-based resin and triglycidyl isocyanurate are mixed according to the formula, extruded by a twin-screw extruder, and then tableted and crushed, and then the tablets are crushed and sieved (160-180 mesh) to prepare catalyst powder; the catalyst powder is sprayed on a metal carrier by an electrostatic spray gun with a spraying thickness of 90-100 μm, and then thermally cured at 200° C. / 10 min to obtain a catalyst coating.

[0024] Beneficial effects:

[0025] The low-temperature denitration catalyst of the present invention is prepared from metal carrier, manganese dichloride, metatitanic acid, ferric chloride hexahydrate, deionized water, hydrochloric acid solution, titanium dioxide, silicon-based resin, triglycidyl isocyanurate, etc. as main raw materials. Then the active component is prepared into catalyst powder with silicon-based resin and triglycidyl isocyanurate, and then electrostatic spraying and high-temperature curing are formed on the metal carrier to form a low-temperature denitration catalyst with high adhesion and high impact resistance. The denitration catalyst layer prepared by the present invention not only has excellent adhesion to the metal carrier, but also has good impact resistance. The 50cm impact catalyst layer has no cracking and falling off phenomenon, which is far better than the denitration catalyst layer currently formed by the impregnation method or precipitation method. The present invention uses a specific high-temperature resistant silicon-based resin and triglycidyl isocyanurate to solidify the catalyst active component on the surface of the metal carrier, realizing the functions of impact resistance, boiling resistance and maintaining the catalyst active component. At the same time, a special manganese catalyst is used to form a hybrid catalyst active component with titanium and iron elements, which is evenly mixed with titanium dioxide and calcined at high temperature to achieve a higher low-temperature catalytic denitrification effect. The low-temperature denitrification effect is better. At 180°C, NO x The conversion rate can reach more than 86%, and it has good water resistance. There is no obvious change after boiling in boiling water for 20 minutes. In the later stage, water can be used to directly clean the catalyst layer to remove pollutants such as dust. It has the advantages of saving denitrification energy consumption, long service life, and not easy to wear.

[0026] The present invention has been described in detail above, but the above embodiments are only illustrative in nature and are not intended to limit the present invention. In addition, this article is not limited by any theory described in the above prior art or invention content or the following examples. DETAILED DESCRIPTION

[0027] The present invention is further described below in conjunction with examples. It should be noted that the following examples are provided for illustrative purposes only and do not constitute a limitation on the scope of protection claimed for the present invention.

[0028] Unless otherwise specified, the raw materials, reagents, methods, etc. used in the examples are conventional raw materials, reagents, methods in the art.

[0029] The epoxy equivalent of triglycidyl isocyanurate is 105 g / mol and was purchased from Changzhou Niutang Chemical Plant Co., Ltd.

[0030] Example 1

[0031] A high-impact-resistant low-temperature denitration catalyst, comprising a metal carrier and a catalyst layer on the metal carrier;

[0032] The metal carrier is a 5-layer tinplate with a layer height of 3.5 cm;

[0033] The catalyst layer includes the following components by mass: 110 parts of active component, 16 parts of silicone-based resin, and 0.9 parts of triglycidyl isocyanurate;

[0034] The active component is prepared from the following raw materials in molar proportions: 7 parts of manganese dichloride, 2 parts of metatitanic acid, 6 parts of ferric chloride hexahydrate, 32 parts of deionized water, and 7 parts of titanium dioxide;

[0035] The silicon-based resin is prepared from raw materials including the following molar proportions: 20 parts of xylene, 8 parts of 1,6-hexanediol, 5 parts of dimethyldimethoxysilane, 8 parts of methylphenyldimethoxysilane, 4 parts of trimethylolpropane, 4.5 parts of succinic anhydride; and a catalyst of dibutyltin dilaurate, the amount of which is 1% of the mass of 1,6-hexanediol.

[0036] The method for preparing the above-mentioned high impact resistance low-temperature denitration catalyst comprises the following steps:

[0037] (1) Deionized water, manganese dichloride, metatitanic acid, and ferric chloride hexahydrate are added to a reaction kettle according to the formula amount, stirred and heated to 82° C. After the mixture is basically dissolved, 30% hydrochloric acid is added dropwise to adjust the pH value of the system to 4-5, and the mixture is stirred and reacted for 1 hour. After the pH value is detected to be stable, titanium dioxide is added in the formula amount and stirred and mixed for 1 hour. After a uniform slurry is formed, the mixture is discharged; the mixture is then placed in a blast oven at 120° C. and dried until the volatile matter is less than 3%; the mixture is then transferred to a muffle furnace and calcined at 410° C. for 4.5 hours; the mixture is cooled to room temperature, crushed and sieved (140-160 mesh) to obtain an active component;

[0038] (2) Add the formulated amount of xylene, 1,6-hexanediol and a catalyst into a reaction kettle, raise the temperature to 120° C., then add the formulated amount of dimethyldimethoxysilane and continue to carry out polymerization reaction at 120° C.; take a sample and detect it by gas chromatography. When the content of free dimethyldimethoxysilane is less than 5%, add the formulated amount of methylphenyldimethoxysilane, and raise the temperature to 130° C. to continue chain extension polymerization reaction; take a sample and detect it by gas chromatography. When the content of free methylphenyldimethoxysilane is less than 1%, it indicates that the organic After the basic reaction of the silicon monomer is completed, a formulated amount of trimethylolpropane is added, and the temperature is raised to 150°C for high-branching chain extension polymerization. During the heating process, the xylene solvent in the system is removed; a sample is taken to detect the hydroxyl value of the polymer. When the hydroxyl value of the polymer reaches 48-55 mgKOH / g, a formulated amount of succinic anhydride is added and the temperature is raised to 160°C for carboxyl end-capping polymerization. When the acid value of the polymer reaches 25-30 mgKOH / g, the material is discharged at high temperature, cooled on a steel belt, and crushed to obtain a silicon-based resin product;

[0039] The active component, silicone-based resin and triglycidyl isocyanurate are mixed according to the formula, extruded by a twin-screw extruder, and then tableted and crushed, and then the tablets are crushed and sieved (160-180 mesh) to prepare catalyst powder; the catalyst powder is sprayed on a metal carrier by an electrostatic spray gun with a spraying thickness of 90-100 μm, and then thermally cured at 200° C. / 10 min to obtain a catalyst coating.

[0040] Example 2

[0041] A high-impact-resistant low-temperature denitration catalyst, comprising a metal carrier and a catalyst layer on the metal carrier;

[0042] The metal carrier is 4 layers of tinplate, with a layer height of 5 cm;

[0043] The catalyst layer includes the following components by mass: 115 parts of active component, 17 parts of silicone-based resin, and 0.9 parts of triglycidyl isocyanurate;

[0044] The active component is prepared from the following raw materials in molar proportions: 6 parts of manganese dichloride, 1.5 parts of metatitanic acid, 5 parts of ferric chloride hexahydrate, 30 parts of deionized water, and 6 parts of titanium dioxide;

[0045] The silicon-based resin is prepared from raw materials including the following molar proportions: 15 parts of xylene, 6 parts of 1,6-hexanediol, 4 parts of dimethyldimethoxysilane, 7 parts of methylphenyldimethoxysilane, 3 parts of trimethylolpropane, 4 parts of succinic anhydride; and a catalyst of dibutyltin dilaurate, the amount of which is 0.8% of the mass of 1,6-hexanediol.

[0046] The preparation method is the same as Example 1.

[0047] Example 3

[0048] A high-impact-resistant low-temperature denitration catalyst, comprising a metal carrier and a catalyst layer on the metal carrier;

[0049] The metal carrier is a 6-layer tinplate with a layer height of 3 cm;

[0050] The catalyst layer includes the following components by mass: 100 parts of active component, 15 parts of silicone-based resin, and 0.8 parts of triglycidyl isocyanurate;

[0051] The active component is prepared from the following raw materials in molar proportions: 8 parts of manganese dichloride, 2 parts of metatitanic acid, 7 parts of ferric chloride hexahydrate, 35 parts of deionized water, and 8 parts of titanium dioxide;

[0052] The silicon-based resin is prepared from raw materials including the following molar proportions: 23 parts of xylene, 9 parts of 1,6-hexanediol, 7 parts of dimethyldimethoxysilane, 10 parts of methylphenyldimethoxysilane, 5 parts of trimethylolpropane, 5 parts of succinic anhydride; and a catalyst of dibutyltin dilaurate, the amount of which is 1.2% of the mass of 1,6-hexanediol.

[0053] The preparation method is the same as Example 1.

[0054] Example 4

[0055] A high-impact-resistant low-temperature denitration catalyst, comprising a metal carrier and a catalyst layer on the metal carrier;

[0056] The metal carrier is a 5-layer tinplate with a layer height of 4 cm;

[0057] The catalyst layer includes the following components by mass: 120 parts of active component, 18 parts of silicone-based resin, and 1.0 part of triglycidyl isocyanurate;

[0058] The active component is prepared from the following raw materials in molar proportions: 7 parts of manganese dichloride, 2 parts of metatitanic acid, 5 parts of ferric chloride hexahydrate, 35 parts of deionized water, and 6 parts of titanium dioxide;

[0059] The silicon-based resin is prepared from raw materials including the following molar proportions: 20 parts of xylene, 9 parts of 1,6-hexanediol, 4 parts of dimethyldimethoxysilane, 10 parts of methylphenyldimethoxysilane, 4 parts of trimethylolpropane, 5 parts of succinic anhydride; and a catalyst of dibutyltin dilaurate, the amount of which is 0.9% of the mass of 1,6-hexanediol.

[0060] The preparation method is the same as Example 1.

[0061] Comparative Example 1

[0062] A currently commercially available vanadium-based denitrification catalyst, Anhui Yuanchen Environmental Protection Technology Co., Ltd., was used as comparative example 1.

[0063] Catalyst performance test

[0064] The SCR catalysts were placed in the SCR denitrification activity test device and the NOx conversion rate was tested under simulated flue gas.

[0065] The experimental conditions are as follows: NO: 350ppm, NH 3 :350ppm,O 2 : 3%, SO 2 : 500ppm, N 2 To balance the gas, the total gas flow rate is 10000ml / min, and the denitrification temperature is 180℃. The gas composition is measured by a flue gas analyzer. NO xConversion rate (%) = [1-(NO x (out) / NO x (In)]*100%.

[0066] The impact resistance test is carried out in accordance with GB / T1732-93 "Determination of impact resistance of paint films".

[0067] The results of the plate making of the embodiment and the comparative example are shown in Table 1:

[0068] Table 1

[0069]

[0070] As shown in Table 1, Examples 1-4 are low-temperature denitration catalysts prepared by the present invention using metal carriers, specific components and processes. The catalyst layer formed by high-temperature curing is dense and uniform, and does not crack after being impacted by 50 cm, indicating that the impact resistance is excellent. At 180 ° C, NO x The conversion rate reached more than 86%. After boiling in boiling water for 20 minutes, the catalyst layer was almost unchanged, and the catalyst activity after boiling in boiling water was almost not significantly reduced. This shows that the specific high-temperature resistant silicone-based resin and triglycidyl isocyanurate solidified the catalyst active components on the surface of the metal carrier, achieving the functions of impact resistance, boiling resistance and maintaining the catalyst active components. At the same time, a special manganese catalyst is used to form a hybrid catalyst active component with titanium and iron elements, which is evenly mixed with titanium dioxide and calcined at high temperature to achieve a higher low-temperature catalytic denitrification effect.

[0071] Comparative Example 1 uses a common commercial vanadium-based denitrification catalyst, which is loaded on an alumina carrier by a precipitation method. The density and uniformity of the catalyst layer are average, and its low-temperature catalytic denitrification effect at 180°C is average. x The conversion rate reached 68.6%. Since the catalyst layer prepared by the precipitation method has poor impact resistance, not only the catalyst layer is severely cracked after impact, but also the alumina carrier is broken at the impact due to its poor toughness. After boiling in boiling water for 20 minutes, the catalyst surface shows obvious loss phenomenon, and the catalyst activity after boiling is also significantly reduced, indicating that the water resistance is also far lower than that of the catalyst product of the present invention.

[0072] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that the technical solutions described in the above embodiments may be modified, or some or all of the technical features thereof may be replaced by equivalents, without departing from the spirit and essence of the claims of the present invention; and these modifications or replacements are still within the scope defined by the claims of the present invention.

Claims

1. A high impact resistance low temperature denitration catalyst, characterized in that: The high impact resistance low temperature denitration catalyst comprises a metal carrier and a catalyst layer on the metal carrier; The catalyst layer comprises the following components by mass: 100-120 parts of active components, 15-18 parts of silicone-based resin, and 0.8-1.0 parts of triglycidyl isocyanurate; The active component is prepared from the following raw materials in molar proportions: 6-8 parts of manganese dichloride, 1.5-2 parts of metatitanic acid, 5-7 parts of ferric chloride hexahydrate, 30-35 parts of deionized water, and 6-8 parts of titanium dioxide; The silicon-based resin is prepared from raw materials including the following molar proportions: 15-23 parts of xylene, 6-9 parts of 1,6-hexanediol, 4-7 parts of dimethyldimethoxysilane, 7-10 parts of methylphenyldimethoxysilane, 3-5 parts of trimethylolpropane, and 4-5 parts of succinic anhydride.

2. The high impact resistance low temperature denitration catalyst according to claim 1, characterized in that: The metal carrier is a multi-layer tinplate plate, with 4-6 layers and a layer height of 3-5 cm, wherein circular small holes are distributed on the tinplate plate, and the interval between every two small holes is 2-3 cm.

3. The high impact resistance low temperature denitration catalyst according to claim 1, characterized in that: The active component is prepared by a method comprising the following steps: Add deionized water, manganese dichloride, metatitanic acid, and ferric chloride hexahydrate into the reaction kettle according to the formula, stir and heat, and adjust the pH value of the system to 4-5 after complete dissolution, continue stirring and reacting, and after the pH value is tested to be stable, add the formula amount of titanium dioxide and stir and mix thoroughly to form a uniform slurry, then discharge the material; Then, it is placed in a blast oven and dried until the volatile matter is less than 3%, and then transferred to a muffle furnace for high-temperature calcination. After the calcination is completed, it is cooled to room temperature, crushed and sieved to obtain the active component.

4. The high impact resistance low temperature denitration catalyst according to claim 3, characterized in that: Raise the temperature to 80-85℃; The temperature of the oven is 110-120°C; The calcination temperature is 380-420°C and the calcination time is 4-5h.

5. The high impact resistance low temperature denitration catalyst according to claim 1, characterized in that: The raw materials for preparing the silicon-based resin also include: a catalyst, which is dibutyltin dilaurate, and the amount used is 0.8-1.2% of the mass of 1,6-hexanediol.

6. The high impact resistance low temperature denitration catalyst according to claim 5, characterized in that: The silicon-based resin is prepared by a method comprising the following steps: A. Add the formulated amount of xylene, 1,6-hexanediol and a catalyst into a reaction kettle, raise the temperature, and then add the formulated amount of dimethyldimethoxysilane to carry out a polymerization reaction; B. Take samples and test them by gas chromatography. When the content of free dimethyldimethoxysilane is less than 5%, add the formulated amount of methylphenyldimethoxysilane and raise the temperature to continue the chain extension polymerization reaction; C. Sampling and testing by gas chromatography, when the content of free methylphenyldimethoxysilane is less than 1%, adding a formula amount of trimethylolpropane, and heating to carry out high-branching chain extension polymerization reaction, while removing the xylene solvent in the system during the heating process; D. Take samples to test the hydroxyl value of the polymer. When the hydroxyl value of the polymer reaches 48-55 mgKOH / g, add the formulated amount of succinic anhydride and increase the temperature to carry out carboxyl-terminated polymerization. When the acid value of the polymer reaches 25-30 mgKOH / g, discharge the material at high temperature, cool it on a steel belt, and crush it to obtain a silicone-based resin product.

7. The high impact resistance low temperature denitration catalyst according to claim 6, characterized in that: In step A, the temperature is raised to 120-125°C; In step B, the temperature is raised to 130-135°C; In step C, the temperature is raised to 150-155°C; In step D, the temperature is raised to 160-163°C.

8. A method for preparing a high impact resistance low temperature denitration catalyst according to any one of claims 1 to 7, characterized in that: The following steps are involved: The active component, silicone-based resin and triglycidyl isocyanurate are mixed according to the formula, extruded by a twin-screw extruder, and then tableted and crushed. The tablets are then crushed and sieved to form catalyst powder; the catalyst powder is sprayed on a metal carrier by an electrostatic spray gun with a spraying thickness of 90-100 μm, and then thermally cured at 200°C / 10 min to obtain a catalyst coating.

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